Recently, the general trends in designing electronic devices are toward small size, light weightiness and easy portability. Moreover, with the increasing development of electronic industries, the internal circuitries of the electronic devices are gradually modularized. In other words, plural electronic components are integrated into a single circuit module. For example, a power module is one of the widely-used circuit modules. An example of the power module includes but is not limited to a DC-to-DC converter, a DC-to-AC converter or an AC-to-DC converter. After the electronic components (e.g. capacitors, resistors, inductors, transformers, diodes and transistors) are integrated as a power module, the power module may be installed on a system circuit board.
A conventional package structure of a power module will be illustrated as follows. Firstly, plural power semiconductor bare chips, plural passive components and plural pins are disposed on a substrate. Through the pins, the power module can be connected with an external circuitry. In particular, the power semiconductor bare chips, the passive components and the pins are welded on the substrate via solder paste. Then, the power semiconductor bare chips, the passive components and the pins are connected with each other through conductive wires by a wire bonding process. Consequently, an exposed power module is produced. Moreover, the power semiconductor bare chips, the passive components and the pins of the exposed power module are covered by an inverted U-shaped covering member. The covering member has plural openings corresponding to the pins. The pins are penetrated through the corresponding pins and partially exposed outside the covering member. Meanwhile, the package structure of the power module is produced. Moreover, the exposed pins may be inserted into corresponding insertion holes of a printed circuit board.
However, the above package structure of the power module still has some drawbacks. For example, since the number and positions of the openings of the covering member are fixed, the covering member is only applied to a specified power module with the fit pin number and pin positions. That is, the utilization flexibility is not satisfactory. If the number and positions of the pins of the power module cannot fit the covering member, the covering member cannot be used for the power module. Under this circumstance, it is necessary to rebuild the new covering member. Consequently, the fabricating cost is increased.
For solving the above drawbacks, another package assembly of the power module was disclosed. The package assembly comprises a non-plate package shell and a power module. Similarly, the power module is an exposed power module. The power module is completely covered by the package shell. The package shell has plural openings in a matrix configuration (e.g., in an M×N matrix configuration). The pins of the power module are penetrated through corresponding openings of the package shell. Since the openings of the package shell are arranged in the matrix configuration, the package shell can be applied to many types of power modules with different pin numbers or pin positions. Under this circumstance, the utilization flexibility is enhanced.
However, if the positions, number and size of the pins of the power module cannot fit the openings of the package shell, the applications of the above package assembly are restricted. In other words, the package shell cannot be applied to all types of power modules. That is, if the positions, number and size of the pins of the power module cannot fit the openings of the package shell, it is necessary to rebuild the new package shell. Consequently, the fabricating cost is increased. Recently, the power module is packaged as an embedded power module. That is, the active component(s) and/or the passive component(s) are embedded within the substrate, and the pins are disposed on the surface of the substrate at the positions corresponding to the active component(s) and/or the passive component(s). Since the number and positions of the active component(s) and/or the passive component(s) embedded within the substrate are diversified, the positions, number and size of the pins are also diversified. In other words, the applications of the above package assembly to the embedded power module are largely reduced.
Therefore, there is a need of providing an improved package assembly in order to eliminate the above drawbacks.